RESUMEN
<p><b>OBJECTIVE</b>To investigate the association between polymorphism of CYP17 gene and serum hormone concentrations in aged men.</p><p><b>METHODS</b>Eighty-three healthy men at the average age of 66.7 were divided into a < 66.7 group (n = 36) and a > 66.7 group (n = 47), and the polymorphism of CYP17 gene in the 5' promoter region was investigated by PCR using DNA from the men's peripheral blood lymphocytes. A new recognition site was created for the restriction enzyme MspA1 I by transition (T --> C) in the risk allele (A2). Three genotypes A1/A1, A1/A2, A2/A2 were established, serum sex-hormone levels measured, and mean hormone concentration evaluated in each genotype and age group.</p><p><b>RESULTS</b>No evidence was found that the testosterone (T) level, estrogen (E2) level and T/E2 ratio were associated with the genotype of CYP17 gene. There was no significant difference in T and E2 levels between the two groups, but there was a significant increase in the T/E2 ratio (P < 0.05).</p><p><b>CONCLUSION</b>A2 allele does not increase sex hormone levels in aged men, but the T/E, ratio was higher in the > 66.7 group than in the < 66.7 group. This may be closely associated with the mechanism of benign prostate hyperplasia and prostate cancer in aged men.</p>